Electric detector-circuit.



F. J. SPRAGUE. ELECTR|C DETECTOR ClRCUIT- N PPLICATION FILED FEB. 26,IBIS.

Patented Dec. 4,1917.

5 SHEETS-SHEET 2 F IG) /Q.

F. J. SPRAGUE.

ELECTRIC DETECTOR-CIRCUIT. APPLICATION FILED FEB-26.1916.

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Patented Dec. 4, 1917.

5 SHEETS-SHEET 4- INVENTOR A TTOR/VEVS F. J. SPRAGUE.

ELECTRIC DETECTOR CIRCUIT.

APPLICATION FILED ra.2e. ms.

248,942. Patented Dec. 4,1917.

5 SHEETS-SHEET 5 FIG. 85.

WITNESSES INVENTOR 6M 4D. W

Wow/78 UNITED STATES PATENT OFFICE.

FRANK T. SPRAGUE, OF SHARON, CONNECTICUT, ASSIGNOR TO SPRAGUE SAFETYCONTROL AND SIGNAL CORPORATION, A CORPORATION OF VIRGINIA.

" ELECTRIC DETECTOR-CIRCUIT.

Specification of Letters Patent.

Patented Dec. 4, 1917.

Original application filed December 31, 1914, Serial No. 879,939.Divided and this application filed February 26, 1916. Serial No. 80,714.

To all whom it may concern:

Be it known that I, FRANK J. SrnAGUE, a citizen of the United States,residing at ,Sharon, in the county; of Litchfield and closed and claimedwithout reference to the question of train control, in that theinvention embodied herein is capable ofother and varied uses, itsobject'being to provlde a detector circuit in which a brief and feebleelectromotive force can be effectively ut1- lized to bring about asubsequent operatlon or cycle" of operations requiring greater dynamiceffort. Obviously, the operation or cycle of operations so produced maybe in turn utilized to accomplish many purposes, but inasmuch as theparticularresults flowing from such operations form no art of thisinvention it is unnecessary .to ere specify them.

'Briefiy stated, the invention here sought to b protected consists of anovel circuit containing a source of constant low potential electricsupply with means for restricting current flow in series with a normallyshunted coil of an electro-magnet, 1n combination with external meansfor momentarily opening said shunt in order to energize the magnet, andmeans controlled by said magnet for prolonging said shunt opening andthe consequent activity of the magnet itself.

The means for opening the shunt may be of the most varied character. Itmay be operated mechanically, magnetically or electrically. Theshunt maybe held springclosed or magnetically or electrically closed againstspring action. If spring-closed it I may be opened'electrically or bymagnetic action, or if held closed by such actionagainst springretraction the shunt may be opened by removal of the closing force.

In. the preferred form illustrated in the present application the shuntis normally spring-closed, but momentarily opened by inducedelectro-magnetic action; and the shunt opening is prolonged by the thenenergized magnet opening the shunt at separate contacts in series withthose first opened before the latter are closed.

Figures 1, 2, and 3 are diagrams illustrating the principle of thisinvention.

Figs. 4, 5, and 6 are diagrams showing the application of the principleillustrated in Figs. 1, 2, and 3 to a circuit containing my invention.

Figs. 7 to 24 show other circuit arrangements falling within theinvention.

Fig. 25 is a diagram illustrating means for automatically effecting atthe expiration of a desired interval the restoration of the circuitparts to normal position.

As the operation of my improved circuit depends initially upon themomentary breaking of contacts in a shunted circuit, instead of themaking of contacts in a series circuit, this operation must bethoroughly considered before its place in my system can be fullycomprehended.

Fig. .1 shows a source of constant low potential (current supply)represented by a attery 1, connected on one side to a noninductiveresistance 2, to prevent (under the condition shown) excess current andexhaustion of battery, from which noninductive resistance, connectionslead to contacts 3 and 4. I The other side of the bat tery connects witha. resistance 5 and with aparallel relation.

Any force applied to the arm 6 sufficient to overcome the tension of itsspring will make physical break, at the contact 3, and if the differenceof potential at the shunted contacts at the moment of physical breakingis negligible there will likewise. be an electric break, no matter ifthe physical movement be not over a thousandth of an inch and the timeinterval of break but of the minutest duration. For all practicalpurposes, the potential at the break can be made sufliciently low to benegligible if the current be taken from a source of low constantpotential through a non-inductive resistance and the break benon-inductive and shunted.

Suppose, however, that it be desired to close the circuit at the contact4, then the force applied must exceed that represented by the increasingtension of its spring as the arm is moved over the intervening gap; andof course any force equal or superior to this will, if applied for asuflicient interval of time, effect closure at this contact.

But suppose that the applied force be only a fleeting effort, in whichcase its energy is measured by time and force, while the energy requiredto move the arm is a definite amount represented by the average tensionof the spring multiplied by the distance through which it-is stretched,increased by such as is represented by the mass movement of the arm.Then, even with a considerable force, if it be applied for a very shorttime only, the arm might not be carried over to engagement, or mightbreak contact at 4.- too quickly to insure the required result sought bysuch contact.

Therefore the conditions obtain, that any force suflicient to move thearm at all will break contact at the contact 3 even if applied for onlya very brief period of time, while considerably larger initial forcesapplied for like intervals of time may not insure closure at, thecontact 4- These simple facts underlie the principle of detectoroperation by momentary contact break, made either mechanically or byfleeting electrical or magnetic impulses, whether direct or alternating,to initiate a subsequent cycle of operations requiring greater dynamiceflorts.

To make this principle available in the form .of apparatus described inthis application, that is, at the instant of breaking contact at 3, toenergize a circuit which shall initiate or actuate a dynamic effort ofsome kind, all that is necessary is to utilize, in the form ofa coil,the resistance 5 in shunt to the contact 3, which prior to the breakingof the contact has a negligible current flowing therein, but which onbreaking contact at the contact 3 instantly becomes active. Or suchshunt can comprise two opposite coils, one in each leg of the shunt, as

p is illustrated in Fig. 2 at 7 and 8, the other elements of the figurebeing the same as in the preceding figure. In thls latter case, it isapparent that while the two coils are ener- Fig. 3 is an operativecircuit diagram showing an application on the principles outlined in thepreceding diagrams. In this, the contact f and its lead are omitted, and

,the circuit from the battery 1, through its resistance 2, is completedthrough a two branch circuit, one branch including the coil 8 and theother the two spring-retracted armatures 9 and 6 impinging upon theseries connected contacts 10 and 3.

l/Vhen in normal position the current from the battery 1 flows throughthe non-inductive resistance 2, and then mainly through the shuntcircuit contacts 10 and 3 in series, a very small portion going throughthe coil 8, which is therefore practically inert, and without strengthenough to retract its armature 9, against the pull ofits spring, sufiiciently to open circuit at the contact 10.

Suppose now that the contact at 3 be broken by movement of the armature6, either mechanically or, for example, by the pull of a relay llenergized momentarily from any source. The shunt path being thus broken,the coil 8 will instantly become active and retract the armature 9,opening the shunt also at the contact 10; and since the contacts 10 and3 are in 'series with each other it is evident that the contact 3 cannow be closed, but that the contact 10 will be kept open by theenergized coil 8. It will also be seen that since the prolonging of theopen shunt condition is effected simply by the breaking ofv a circuit ata secis insured also by the breaking of contact 10 at the beginning ofthe motion of armature 9, and coil 8 is constantly potentialized,

so that its current increment takes place practically instantly onthe'breaking of contact 3. Once the coil 8 has become energized itremains energized until its: circuit is broken by other means than thoseindicated in the figure. It thus performs the function of a maintainingcoil during the energization of which current flows through theresistance 2.

Although, manifestly, the contact :3 may be broken m a variety of ways,and the variants of sequential results are many, fundamentally theprinciple illustrated in Figs. 1 to 3 is unchanged; for whatever theminor current in said circuit, and external means for opening the shuntaround the magnet, such opening being prolonged by the maintaining coil.

The relay 11 can be consideredfor all intents and purposes theinitialactive element of my detector system, or for brevity, the actuator.

I have described a maintaining coil whose function is to continue theaction of a mo? mentary break in a circuit, but its action is distinctlydiflerent from that of the maintaining coils used in, for example, mymultiple-unit system for railways, described in Patent No. 660,065.

' In the latter type a coil normally opencircuited iS'iIl series with.two contacts in parallel relation to eachother, one of which is closedby some external agency and the other of which is closed by action ofthe maintaining coil itself when energized, the latter remaining closedwhile the first mentioned contact in parallel with it is broken.

In the preferred form of maintaining coil and circuit which formelements of the detector I have described in this specification, thecore of the maintaining coil is normally dead, and a normally livecircuit is maintained in a shunt around the maintaining coil through twocontacts in series, one of which may be broken by an external agency andthe other by the maintaining coil when it becomes energized because ofthat break.

The one form depends upon the making of contacts which are in parallelwith each other and in series with the maintaining coil, while the otherdepends upon the breaking of contacts which are in series with eachother but are in a circuit parallel with the maintaining coil.

Figs. 4 to 24 inclusive, illustrate the principle and circuit action ofthe detector under varying conditions. The battery 1 is not shown, butthe leads from its terminals are illustrated by vertical lines at theleft and right of each figure respectively, a constant low potentialsource in circuit with the leads being assumed. H

Figs. 4 to 6 inclusive show the maintaining coil 8 connected across thebattery leads through the resistance 2. The maintaining coil has aroundit a low resistance shunt comprising the armature 6 and contact 3. Thedetector relay 11 is also connected across the battery leads, through'pivotally mounted spring-retracted switches 12 and 13 in series. Thedetector relay is wound on the same core as the maintaining coil.

Fig. 4 shows the switch 12 closed and the switch 13 open, with currentflowing through the resistance 2 and the shunt formed by the armature 6and contact 3 around the maintaining coil 8, while the detector relay 11is dead.

In Fig. 5 the switch 13 is closed, the switch 12 remaining closed also.Current flows through the detector relay and the magnet core common tothe two coils is energized, pulling down the armature 6 and breaking theshunt circuit at the contact 3. The current now passes through themaintaining coil, and if direct current is used and the coils are woundin proper relation the current in the maintaining coil will cooperatewith the current in the detector relay to hold down the armature 6. andkeep the shunt circuit open.

In Fig. 6 the switch 13 has been further depressed, breaking contact atthe switch 12 85 and open-circuiting the detector relay; but the circuitin the maintaining coil remains closed and the armature 6 is stillretracted, so that the shunt is kept open at the contact 3, and thecore, under the influence of the maintaining coil, remains energized. Bya as in Figs. 4 to 6, except that it has a separate core from that ofthe relay coil 11.

The latter, however, is shown supplied from a source independent fromthat of the maintaining coil, such source being in these figures thesecondary winding 14 of a generator, the primary magnet of which isdesig: nated by 15. The armature 6 is lengthened out to extend over thecores of both coils.

In Fig. 7 the magnet 15 is shown as dead, with the consequent conditionof deenergization of the detector relay, so that the current flowsthrough the shunt to the main taining coil and the latter is dead.

In Fig. 8 the magnet 15 is illustrated as momentarily energized with aconsequent energization by induction of the detector ,relay. This drawsdown the armature 6 from the contact 3, and breaks the shunt so that themaintaining coil becomes energized. This in turn acts on the armature 6,and when the detector relay becomes denergized,'as in Fig. 9, preventsthe shunt circuit being reestablished. Y

Figs. 10 to 12 show a similar arrangement to that of Figs. 7 to 9, inthat the maintaining coil, its connections and its shunts are similar tothose of the last named. figures, and the detector relay coil isindependently energized. The coils, however, instead of being locatedboth on the same side I of the armature pivot, are located on oppositesides, and the armature 6 (still acting in double capacity) is pivotedcentrally between them.

In Fig. 10 the magnet 15 and the detector relay are both dead, so thatthe current flows through the shunt to the maintaining coil, and thelatter is dead.

In Fig. 11 the magnet 15 and the detector relay are momentarily alive,so that the armature 6 is drawn toward the latter coil and rotated onits pivot, and the shunt to the maintaining coil is broken at thecontact 3. The maintaining coil is thus energized, and when the detectorrelay is dead, as in Fig. 12, the maintaining coil 8 maintains thearmature in the same position as in Fig. 11 and continues the break inthe shunt circuit.

In Figs. 13 to 15, the circuit of the maintaining coil 8 is the same asin the preceding figures under discussion, but its shunt has two breaksin series, as in Fig. 3, and comprises the armature 6 and contact 3 ofthe detector relay 11 and its own armature 9 and contact 10.- The mannerof energizing the detector relay is not shown, but it is under-. stoodthat it can be energized from any suitable source.

In Fig. 13 the detector relay is shown dead and the current flowsthrough the shunt of the maintaining coil, which coil is dead.

In F ig.' 14 the detector relay is momentarily energized, its armature 6drawn away from the contact 3 and the shunt circuit broken, whichimmediately results in the energizing of the maintaining coil and awithdrawing of its armature 9 from the contact 10.

In Fig. 15 the detector relay is shown as dead and its armature as oncemore making contact with the contact 3; but the shunt circuit ismaintained open at the vcontact 10 by the armature of the'livemaintaining coil still being retracted.

Figs. 16 to 18 illustrate how the maintaining coil can be made use of inconnection with a third or operating coil 16. The arrangement of thedetector relay and maintaining coils, their circuit and the shunt to themaintaining coil are the same as in Figs. 13 to 15.

I The operating coil 16 is connected at one end with one of the batteryleads, and connection to the-other lead is made whenever the armature'9of the maintaining coil 8 is drawn up against its back contact 17 withwhich the operating coil is connected. The operating coil is shown aprovided with an armature 18. a

Fig. 16 shows the same condition in respect to the detector relay andmaintaining coils and their armatures and circuits as Fig. 13, so thatthe operating coil is dead.

Fig. 17 shows the same condition in respect to the detector relay andmaintaining coils and their armatures and circuits as retains itsarmature against contact 17, and

the circuit of the operating coil is still complete.

The operating coil and its armature are serviceable for any purpose towhich they are adapted.

In Figs. 19 to 24, I have shown the detector relay and maintaining coilsand their circuits in a slightlv diflerent arrangement than in the otherdrawing of this series, commencing with Fig. 4, and may be said torepresent a combination of the drawings, Figs. 2 and 3. Commencing withFig. 4:, the maintaining coil is shown as being in series with anon-inductive resistance and as being provided with a very lowresistance shunt; but in Figs. 19 to 24 the maintaining coil isconnected directly across the battery leads and is normally energized.On the same core with the maintaining coil is mounted differentially anequal and opposing coil 7, the two coils neutralizing their respectiveeflect upon the core when both are energized. The differential coilialso connected across the battery leads, and in series with it are thedetector relay coil armature 6, contact 3, contact 10, and maintainingcoil armature 9. The manner of energizing the detector relay 11 is notshown, but may be from any source.

In Fig. 19, the detectorrelay is shown as dead and contact 3 closed; themaintaining coil armature i shown as retracted against the contact 10.Current, therefore, flows through both the maintaining coil and thedifferential coil as indicated by the arrows, but as the differentialand maintaining coils are equal and opposing, their common core is deadand the contact 10 is closed.

In Fig. 20 the detector relay is shown as energized and its armaturedrawn away from the contact 3. This breaks the circuit of thedifferential coil, and the core of the maintaining coil now becomesenergized and the contact 10 is broken, so that there are two breaks inseries in the circuit of the differential coil.

Fig. 21 shows the detector relay deenergized and its armature returnedto-the contact 3, but the circuit of the difierential coil 'is stillbroken at the contact 10, and the break maintained by the action of thelive maintaining coil.

Figs. 22 to 24 inclusive, illustrate the arrangement of Figs. 19 to 21inclusive, with a showing of one method of.connecting up the operatingcoil with such an arrangetaining coil armature 9 is as in Figs. 16

Fig. 22 shows the same condition in respect to the detector relay,maintaining and differential coils, and the armatures and circuits, asFig. 19, so that the core of the open ating coil is dead.

Fig. shows the same condition in respect to the detector relay,maintaining and differential coils, and the armatures and circuits, asFig. 20, so that the contact 17 is closed and a circuit is establishedthrough the operating coil. The armature of the operating coil is, as inFig. 17, drawn up thereby.

Fig. 241 shows the same condition of the detector relay, maintaining anddifferential coils, and-the armat-ures and cincuits as Fig. 21, with aconsequent maintaining of the circuit in the operating coil.

Thus the same thing is accomplished with the arrangement of the last sixfigures as with the arrangement of the other figures of the series.Broadly speaking, the energizing of the detector relay causes a break ina circuit parallel to the maintaining coil, which makes the latteroperative, and when so operative it maintains itself operative and isnot affected by the deener'gizing of the detector relay.

The operating coil or the circuits controlled thereby may have anycharacter or function desired, the resultant action occupying either ashort or a long time, and requiring small or large effort, although theinitiation through the detector relay may be of the briefest durationand attenuated character, but as stated the specific nature of suchcharacter or function forms no part of the invention sought to beprotected herein.

It has been before stated that upon the energization of the maintainingcoil it remains energized until its circuit is broken. This may beconveniently accomplished by a suitable switch located in its circuit,but in Fig. 25 I have shown means for accomplishing this automaticallyat the expiration of a desired time interval. In this figure all theelements shown in Figs. 16 to 18 are present, the non-inductiveresistance 2 being shown as a lamp, but between the maintaining coil andthe non-inductive resistance is included a pair of contacts 19 and 20,which when bridged by a commutator 21, complete the circuit thereof. Thecommutator is suitably driven by a train 22 and has a definite period ofrotation when released, it bein normally restrained in posit-ion tobridge t e contacts by a detent 23 on thearmature 18 of the'opcratingmagnet 16. When such magnet is energized, as described in connectionwith Figs. 16 to 18, the detent releases the commutator, which inrotation breaks the circuit of the maintaining magnet, which thenreleases its armature 9 to complete the shunt around it and break thecircuitof the operating magnet. The continued rotation of the commutatorbefore it is brought to rest by the detent again makes the circuit ofthe maintaining magnet when the above cycle of operations may berepeated. Additional contacts 24, 25 and 26 may be provided to close, inconjunction with the commutator,- circuits for effecting desiredresults.

The foregoing detailed description has been given for clearness ofunderstanding, and no undue limitation should be deduced therefrom, butthe appended claims should be construed as broadly as permissible inview of the prior art.

Having thus described my invention, what I claim and desire to secure byLetters Patent is 1. The combination with a normally closed circuitcontaining a source of constant potential and a coil, a normally closedshunt around the coil, and means for opening the shunt and for therebycausing the coil to maintain the shunt open.

2. The combination with a normally closed circuit containing a source ofconstant potential and a coil and a current limiting resistance. of anormally closed shunt around the coil, and means for momentarily openingthe shunt and for thereby causing the coil to open the shunt circuitindependent of the subsequent closing of the initially opened contact. I

3. The combination with a normally closed circuit containing a source ofconstant low potential and a coil in series therewith, of a plurality ofnormally closed contacts in series with each other and in shunt to saidcoil, and means for opening the shunt at one of said contacts, anotherof said contacts being opened by the coil to maintain the opening of theshunt independent of the subsequent closing of the initially openedcontact.

1. The combination with a normally closed circuit containing a source ofconstant potential and a relay coil in series therewith, of a pluralityof normally closed contacts in series with each other and in shunt tosaid coil, and means for opening the shunt at one of said contacts,another of said contacts being opened by the relay to maintain theopening of the shunt independent of the subsequent closing of theinitially opened contact.

stant potential and a coil, a normally closed shunt around the coil,means for opening the shunt and for thereby causing the coil to maintainthe shunt open, and means for then closing the shunt.

6. The combination with a normally closed circuit containing a source ofconstant potential and a coil, a normally closed shunt around the coil,means for opening the shunt and for thereby causing the coil to maintainthe shunt open, and a timing element controlled by the coil for closingthe shunt.

7. The combination with a normally closed circuit containing a source ofconstant potential and a coil, a normally closed shunt around thecoil,means for opening the shunt and for thereby causing the coil to maintainthe shuntiopen, and a timing ele-.

ment controlled by the coil put in motion on the opening of the shunt toclose the shunt.

8. The combination with a normally closed circuit containing a source ofconstant potential and a relay coil in series therewith, of a pluralityof normally closed contacts in series with each other and in shunt tosaid coil, means for opening the shunt at one of said contacts, anotherof said contacts being opened by the relay to maintain the opening ofthe shunt independent of the subsequent closing of the initially openedcontact, and means for deenergizing the coil.

9. The combination with a normally closed circuit containing a source ofconstant potential and a relay coil in series therewith, of a pluralityof normally closed contacts in series with each other and in shunt tosaid coil, means for opening the shunt at one of said contacts, anotherof said contacts'being opened by the relay to maintain the opening ofthe shunt independent of the subsequent closing of the initially openedcontact, and a timing controlller for automatically de'e'nergizing the001 10. The combination with a normally closed circuit containing asource of constant potential and a relay coil in series therewith, of aplurality of normally closed contacts in series with each other and inshunt to said coil, means for opening the shunt at one of said contacts,another of" saidcontacts being opened by the relay to maintain theopening of the shunt independent of thesubsequent closing of theinitially opened contacts, and a timing controller put in motion by the.energization of the relay to deenergize the same.

In testimony whereof I have signed my name.

FRANK J. SPRAGUE.

